1. Field of the Invention
The invention relates to a switch, and more particularly to an electrical switch and a method of producing the same.
2. Description of the Related Art
Referring to FIG. 1, a conventional rolling-ball switch 1 includes a housing 11, four metallic pin terminals 12 (only two is shown) arranged in an array and partially inserted into the housing 11, and a ball member 13 disposed in the housing 11 and contacting the pin terminals 12.
In normal use, the ball member 13 is simultaneously in contact with the pin terminals 12 to place the rolling-ball switch 1 in an ON state. When an external force is applied to the switch 1 so that the ball member 13 is moved away from one of the pin terminals 12, the switch 1 is shifted to an OFF state.
Referring to FIGS. 2 to 4, in combination with FIG. 1, during making of the pin terminal 12, a square-shaped blank 12′ that extends along a long-axis direction (X) is formed by drawing or punching. Afterwards, a punch (not shown) is moved along a short-axis direction (Y) of the blank 12′ to shear punch each corner 121′ of the blank 12′ consecutively by moving along a punching direction (C) toward a punching line 14, so that the pin terminal 12 is formed with four guide inclined sheared surfaces 121.
However, because each guide inclined sheared surface 121 is in contact with the punch during punching that causes a plastic deformation thereof, a roll over zone (I) having a smooth burr-free surface is formed. Afterwards, when bearing an external force that is lower than the tensile strength thereof, a shear zone (II) having a shiny surface is formed. Finally, when bearing an external force that is greater than the tensile strength thereof, a rupture/fracture zone (III) and a burr zone (IV) having surfaces that are approximately torn are formed.
Based on the aforesaid description, when each pin terminal 12 is assembled into the housing 11, because the fracture zone (II) and burr zone (IV) of the pin terminal 12 are rough and occupy a large area, they may scratch the housing 11 and provide a resistance during insertion of the pin terminal 12 into the housing 11. Furthermore, after assembly, the aforesaid rough surfaces, especially the burr zone (IV), may affect contact area with the ball member 13, so that efficiency of the conventional rolling-ball switch 1 is also affected.